Justina (5) , empress, second wife of Valentinian I., a Sicilian by birth, and, teste Zosimus (iv. 19 and 43), the widow of Magnentius, killed in 353. Valentinian may have divorced his first wife ( Chron. Pasch. 302), and then espoused Justina, probably in 368.
She was an Arian, but during her husband's lifetime concealed her opinions (Ruf. H. E. ii. 15, in Migne, Patr. Lat. xxi. 523). She, however, endeavoured to prevent him from allowing St. Martin of Tours to enter his presence (Sulp. Sev. Dial. ii. in ib. xx. 205). After her husband's death she at once used her influence as mother of the infant emperor Valentinian II. to advance the interests of her sect, and soon came into collision with St. Ambrose. Their first contest was probably c. 380, when St. Ambrose was summoned to Sirmium to take part in the consecration of Anemius as bishop of that see, the empress being desirous that the new bishop should be consecrated by the Arians (Paulinus, Vita S. Ambrosii , in ib. xiv. 30).
After the murder of Gratian and the seizure by Maximus of Spain, Gaul, and Britain in 383, Justina (who, with her infant son, was residing in the imperial palace at Milan) had recourse to her former opponent St. Ambrose. She placed her son in his hands, and induced him to undertake the delicate task of going as ambassador to Maximus, to persuade him to be contented with Gratian's provinces and to leave Valentinian in undisturbed possession of Italy, Africa, and Western Illyricum (St. Ambrose, Epp. 10, 21, 24; Id. de Obitu Valentiniani , 1182 in Patr. Lat. xvi. 1001, 1007, 1035, 1368). His mission was successful, at any rate for a time; but the ungrateful Justina assailed him at Easter 385 with the object of obtaining a church at Milan for the use of her fellow-Arians. For an account of this memorable struggle see AMBROSIUS. By a constitution (Cod. Theod. xvi. 1, 4), dated Jan. 21, 386, and drawn up at her direction (Soz. H. E. vii. 13), those who held the opinions sanctioned by the council of Ariminum were granted the right of meeting for public worship, Catholics being forbidden under pain of death to offer opposition or to endeavour to get the law repealed.
When danger again threatened, Justina again had recourse to Ambrose's services. After Easter 387 he was sent to Trier to ask that the body of Gratian should be restored to his brother and to avert Maximus's threatened invasion of Italy (Ep. 24). His mission was unsuccessful; Maximus crossed the Alps in the autumn and made himself master of Italy without striking a blow. Valentinian and his mother and sisters fled by sea to Thessalonica, whence she sent to Theodosius imploring his help. Zosimus (iv. 44) narrates how she overcame his reluctance by the charms of her daughter, the beautiful Galla, whose hand paid for his assistance. (See Duc de Broglie, L᾿Eglise et l᾿emp. iii. 228.) In 388, the year of her son's restoration, Justina died (Soz. H. E. vii. 14; Ruf. H. E. ii. 17).
[F.D.]